KR20140080491A - New and stable aqueous hybrid binder - Google Patents

Abstract

The present invention provides novel stable colloidal silica-containing polymeric binders that are simply processed without modification, and novel coating compositions, particularly aqueous coating compositions, that have more efficient pollution resistance / removal capabilities at a reasonable and manageable cost.

Description

[0001] The present invention relates to a stable new aqueous hybrid binder,

The present invention relates to stable aqueous hybrid binders containing colloidal silica, and uses thereof.

Colloidal silicas have long been used as coating materials for improved adhesion, as well as wear resistance and water resistance of various materials. However, these dispersions, especially highly concentrated colloidal silica dispersions, are difficult to store for a long period of time because of easy gelation and precipitation of the silica.

The colloidal silica in the polymer coating can be modified immediately aiming at properties such as scratch resistance, UV protection or conductivity. Control of dispersion and surface modification of the colloidal silica determines the clear appearance of the coating and its properties.

Conventional methods have been pursued to introduce colloidal silica into coating composition formulations. The colloidal silica can be mixed directly with the resin or curing agent component, or with the coating composition ready for application. In aqueous systems colloidal silica is likely to be dispersed in the aqueous phase. The preparation of the colloidal silica as one of the binder components and the surface control for the resin or curing agent component has been further described.

From a practical point of view, it is advantageous to disperse the colloidal silica in one component as a stable masterbatch to ensure ease of handling of the lacquer formulation and long-term storage stability. In the final use, the colloidal silica can also be easily dispersed in a finely divided manner, so that advantageous properties such as transparency, scratch resistance or conductivity can be obtained.

In practice, the colloidal silica is usually dispersed in the resin component, the aqueous phase or the final mixture of the curing agent and the resin just prior to curing. Generally, this requires adjusting the surface of the colloidal silica to a specific matrix of adhesive or coating composition. A disadvantage of simple mixing of the modified colloidal silica is that it depends on the stability of the complete preparation, i. E., All formulation components. If there is variation in one parameter, the components can be separated (Pilotek, Steffen, Tabellion, Frank (2005), European Coating Journal, 4, 170 et seq.).

US20090163618A1 claims an aqueous binder dispersion based on silane-modified polymeric binders and inorganic nanoparticles, a process for its preparation and its use for producing high quality coatings, in particular transparent lacquers.

WO2001018081A1 claims a process for preparing an aqueous dispersion of composite particles consisting of a polymerization product and a micro-inorganic solid material. According to this method, at least one ethylenically unsaturated monomer is dispersed in an aqueous medium, and at least one radical polymerization initiator is used in the presence of at least one dispersed fine inorganic solid material and at least one dispersing agent, .

Prior art methods require special silanization of the polymer, or isomerization in the presence of a specific dispersant.

Thus, there remains a need in the art for a stable, colloidal silica-containing, polymeric binder that is new and simply handled without modification, and new coating compositions, particularly aqueous coating compositions, that have more efficient pollution resistance / do.

DESCRIPTION OF THE INVENTION

The present invention provides a composition comprising: a) at least one water dispersible or water soluble polymer comprising, as copolymerized units, ethylenically unsaturated monomers having at least one functional group, in an amount of 1 to 10 wt%, based on the dry weight of the polymer; And b) at least one colloidal silica; Wherein the surface acid value of the water dispersible or water soluble polymer is 1.0 to 4.0 mg KOH / dry polymer g, the serum phase acid value is 0 to 2.3 mg KOH / dry polymer g, and the final pH value is at least 8.5 To provide a controlled, stable aqueous hybrid binder.

The present invention also provides a coating composition comprising a binder.

details

In describing the components in the compositions of the present invention, all phrases containing parentheses are intended to encompass inserts therein, inserts being omitted, or both. For example, the phrase "(co) polymer" optionally includes polymers, copolymers, and mixtures thereof; The term "(meth) acrylate" means acrylate, methacrylate, and mixtures thereof.

The term "aqueous" as used herein means water which is mixed with not more than 50 wt% water-miscible solvent, based on the weight of the water or mixture.

The term "polymer" as used herein includes resins and copolymers.

The term "acryl ", as used herein, refers to (meth) acrylic acid, (meth) alkyl acrylate, (meth) acrylamide, (meth) acrylonitrile and modified forms thereof, Rate and so on.

The term "average particle size (or diameter)" as used herein, unless otherwise indicated, is measured using a MULTISIZER ^TM 3 Coulter counter (Beckman Coulter, Inc., Fullerton, Calif. Refers to the median particle size (or diameter) of the particle distribution. The medium is defined as 50 wt% of the distributed particles being smaller than the medium and 50 wt% of the distributed particles being larger than the medium. This is the volume average particle size.

As used herein, the term "Tg " means the glass transition temperature measured with a differential scanning calorimeter (DSC) using a heating rate of 20 [deg.] C / min unless otherwise indicated and taking the inflection point as the Tg value in the thermogram. The term "calculated Tg" refers to the Tg of a polymer determined using the Fox equation (T. G. Fox, Bull. Am. Physics Soc., Volume 1, Issue No. 3, page 123 (1956)). The Tg of the homopolymer can be determined, for example, in "Polymer Handbook", edited by J. Brandrup and E.H. Immergut, Interscience Publishers]. For multistage polymers, the reported Tg value will be a weighted average of the inflection points observed in the thermogram. For example, a two-stage polymer consisting of an 80% soft first stage and a 20% hard second stage polymer with one DSC inflection point at 68 ° C and one at -43 ° C will have a reported Tg of -20.8 ° C.

The term "acid value" refers to the amount of acid determined by how much potassium hydroxide is needed between two peaks of the first derivative of the titration curve - the titration titration acid-base titration curve per dry polymer.

The aqueous hybrid binder of the present invention has an average particle diameter of 50 to 800 nm, a minimum film forming temperature of -35 占 폚 to 60 占 폚, and a surface acid value of 1.0 to 4.0 mg KOH / dry polymer g, a serum acid value of 0 to 2.3 mg KOH / g of at least one water dispersible or water soluble polymer.

During the synthesis of the copolymer, the acid is distributed on the surface of the particles, on the surface of the particles, or embedded in the particles. The surface acid is defined as the acid part distributed on the particle surface, and the acidic acid in the serum is defined as the acid part distributed on the serum. The seramic acid moiety is separated, collected by spinning down of the latex (using centrifugation), and protonated with a solution of hydrogen chloride. The latex is then redispersed in water and protonated with a hydrogen chloride solution. After the treatment, the surface acid value and the serum acid value of the polymer can be measured separately by plotting the relationship between the amount of addition of potassium hydroxide (KOH) and the electroconductivity. The surface acid number and the acid number in the serum can be calculated from the KOH addition between two peaks of the first derivative of the titration curve.

In the present invention, a water-dispersible or water-soluble polymer having a surface acid value of 1.0 to 4.0 mg KOH / dry polymer g and a serum acid value of 0 to 2.3 mg KOH / dry polymer g is used. More preferably, a water-dispersible or water-soluble polymer having a surface acid value of 1.75 to 3.43 mg KOH / dry polymer g and a serum acid value of 0.07 to 1.5 mg KOH / dry polymer g is used.

The water dispersible or water soluble polymer is copolymerized from ethylenically unsaturated nonionic monomers. In this case, "nonionic monomer" means that the copolymerized monomer residue has no ionic charge between pH 1 and 14. [ The ethylenically unsaturated nonionic monomer used in the present invention is, for example, a (meth) acrylic ester monomer, wherein the (meth) acrylic ester is a methacrylic ester or an acrylic ester, and includes methyl acrylate, ethyl acrylate, butyl Acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hydroxyethyl methacrylate, hydroxy Propyl methacrylate); (Meth) acrylonitrile; (Meth) acrylamide; Amino-functional and ureido-functional monomers; Monomers having acetoacetate-functional groups; Styrene and substituted styrene; butadiene; Ethylene, propylene,? -Olefins such as 1-decene; Vinyl acetate, vinyl butyrate, vinyl versatate and other vinyl esters; And vinyl monomers such as vinyl chloride, vinylidene chloride.

The water-dispersible or water-soluble polymer of the present invention is prepared by polymerizing an ethylenically unsaturated monomer having at least one functional group selected from carboxyl, carboxylic acid anhydride, hydroxyl, amide, sulfonate, phosphonate and mixtures thereof, By weight to 10 wt% or less, preferably 5 wt% or less, more preferably 2.5 wt% or less. Examples of these types of monomers are ethylenically unsaturated carboxylic acids or dicarboxylic acids, in particular acrylic or methacrylic acid, itaconic acid, maleic acid, or amides, in particular N-alkylolamides or hydroxyalkyl esters of the abovementioned carboxylic acids, Acrylamide, N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, hydroxyethyl (meth) acrylate, and hydroxypropyl (meth) acrylate. More preferably, the working monomers are methyl acrylate, acrylic acid, acrylamide, methacrylamide. Most preferably, the working monomer is methyl acrylate.

Optionally, the copolymer comprises, as copolymerized units, from 0 to 0.5 wt%, preferably from 0.05 wt% to 0.4 wt% of at least one ethylenically unsaturated monomer having at least one alkoxysilane functionality, preferably a hydrolysable alkoxysilane functionality, , More preferably from 0.1 wt% to 0.3 wt%. Alkoxysilane functional monomers include, for example, vinyltrialkoxysilanes such as vinyltrimethoxysilane; Alkyl vinyl dialkoxysilanes; (Meth) acryloxyalkyltrialkoxy-silanes, such as (meth) acryloxyethyltrimethoxysilane and (meth) acryloxypropyl-trimethoxysilane; And derivatives thereof.

The alkoxysilane functional monomer may be added during copolymerization of the copolymer, or after copolymerization of at least one ethylenically unsaturated nonionic monomer and at least one alkoxy silane-capable precursor monomer. As used herein, the term "alkoxysilane-capable precursor monomer" refers to an alkoxysilane-capable precursor monomer that, after copolymerization, provides an alkoxysilane-containing functional group bonded to a copolymer, e. G., A copolymer containing epoxysilane or aminosilane, Quot; refers to a monomer having a reactive group capable of reacting with the alkoxysilane-containing compound to form a silane-containing copolymer.

The polymerization techniques used to prepare the copolymers are well known in the art, for example by emulsion polymerization. In emulsion polymerization processes, conventional surfactants, such as alkali metal or ammonium salts of anionic and / or nonionic emulsifiers, such as alkyl, aryl or alkylaryl sulfates, sulfonates or phosphates; Alkyl sulfonic acids; Sulfosuccinate salt; fatty acid; Ethylenically unsaturated surfactant monomers; And ethoxylated alcohols or phenols may be used. The amount of surfactant used is generally from 0.1 to 6% by weight, based on the weight of the monomer. A thermal or redox initiation method may be used. The reaction temperature is typically maintained at a temperature below 100 占 폚 through the pre-reaction step. The reaction temperature is preferably from 30 to 95 캜, more preferably from 50 to 90 캜. The monomer mixture may be added neat or in water emulsion. The monomer mixture may be added one or more times during the reaction period in an addition manner or continuously, linearly or non-linearly, or a combination thereof.

Typical free radical initiators such as hydrogen peroxide, sodium peroxide, potassium peroxide, t-butyl hydroperoxide, cumene hydroperoxide, ammonium and / or alkali metal persulfate, sodium perborate, superphosphate and salts thereof, potassium permanganate And ammonium or alkali metal salts of peroxy sulfuric acid, and the like, can be used at levels of typically from 0.01 to 3.0% by weight, based on the weight of the total monomers. Suitable reducing agents include, for example, sodium sulfoxylate formaldehyde, ascorbic acid, isoascorbic acid, alkali metal and ammonium salts of sulfur-containing acids such as sodium sulfite, bisulfite, thiosulfate, hydrosulfite, Amides such as sulfide or dithionite, formadinedisulfonic acid, hydroxymethanesulfonic acid, acetone bisulfite, ethanolamine, glycolic acid, glyoxylic acid hydrate, lactic acid, glyceric acid, malic acid, tartaric acid and salts of these acids A redox system using the same initiator that is coupled to < / RTI > Redox reaction catalyzed metal salts of iron, copper, manganese, silver, platinum, vanadium, nickel, chromium, palladium or cobalt may be used. Chelating agents for metals may optionally be used.

A buffer is optionally used in the present invention. It is a kind of salt and is used to control the process pH value during the polymerization reaction. Common buffer salts include phosphates, citrates, bicarbonates, acetates and carbonates. Counter ions may be sodium, potassium, and ammonium ions. The buffer may be added in most or all of the entire reaction period, or in one or more additions during the limited portion (s) of the reaction period or continuously, linearly or not. The process pH value can be adjusted between 2 and 7 using a buffer. The preferred process pH value is 2 to 5. A more preferred process pH value is 2 to 4.

Chain transfer agents, for example, halogen compounds such as tetrabromomethane; An allyl compound; Or alkylthioglycolate, alkylmercaptocarnonate and mercaptans such as C ₄ -C ₂₂ linear or branched alkyl mercaptans can be used to lower / lower the molecular weight of the emulsion polymer or to lower the molecular weight of the emulsion polymer obtained with any free radical generation initiator May be used to provide a different molecular weight distribution. The chain transfer agent (s) may be added in one or more additions or continuously, linearly or non-linearly throughout most or all of the overall reaction period, or in the kettle filler and residual monomer reduction stages during the limited portion (s) of the reaction period . The chain transfer agent is typically used in an amount of 0 to 5 wt% based on the total weight of the monomers used to form the aqueous copolymer dispersion. Preferred chain transfer agent levels are from 0.01 to 0.5, more preferably from 0.02 to 0.4 and most preferably from 0.05 to 0.2 mole percent, based on the total moles of monomers used to form the aqueous copolymer dispersion.

In another embodiment of the present invention, the aqueous emulsion polymer may be prepared by a multi-stage emulsion polymerization process in which at least two stages differing in composition are polymerized in a sequential manner. Such processes sometimes result in the formation of at least two mutually incompatible polymer compositions resulting in at least two phases within the polymer particles. Such particles may be comprised of two or more phases of various geometries or shapes, for example, core / shell or core / sheath particles, core / shell particles in which the shell phase is incompletely encapsulating the core, Particles and interconnected network particles. In all of these, the majority of the particle surface area will consist of at least one external phase, and the interior of the particle will consist of at least one internal phase. The multistage emulsion polymer in each step may contain the same monomers, surfactants, chain transfer agents, and the like, as described herein above for the emulsion polymer. For multistage polymer particles, the Tg for the present invention can be calculated in Fox form as described in detail herein using the total composition of the emulsion polymer, regardless of the number of phases or phases therein. Similarly, for multistage polymer particles, the amount of monomer will be calculated using the total composition of the emulsion polymer, regardless of the number of phases or phases therein. For example, the first stage composition consists predominantly of styrene and the second stage consists of the composition described in the present invention. In addition, the core of the copolymer particles may be hollow (i.e., air voids). The polymerization techniques used to prepare such multistage emulsion polymers are well known in the art and are described, for example, in U.S. Patent Nos. 4,325,856; 4,654,397; And 4,814,373. Preferably, the monomers are contained only in one stage of the multistage emulsion polymerization.

The average particle size of the copolymer dispersion particles is from 50 to 350 nanometers, preferably from 50 to 300 nanometers, as measured by a BI-90 particle sizer.

Colloidal silica particles, also referred to herein as silica sols, such as precipitated silica, microsilica (silica fume), pyrogenic silica (fumed silica), or silica gels with sufficient purity, Lt; / RTI >

The colloidal silica particles and silica sol according to the present invention may be modified and contain other elements which may be present in the particles and / or in the continuous phase, such as amine, aluminum and / or boron. Boron-modified silica sols are described, for example, in U.S. Patent No. 2,630,410. The aluminum-modified silica particles suitably have an Al ₂ O ₃ content of from about 0.05 to about 3 wt%, preferably from about 0.1 to about 2 wt%. The preparation process of the aluminum-modified colloidal silica is described in, for example, " The Chemistry of Silica ", by Iler, K. Ralph, pages 407-409, John Wiley & Sons (1979) and U.S. Patent No. 25,368,833 ≪ / RTI >

The colloidal silica particles suitably have an average particle diameter of from about 2 to about 150 nm, preferably from about 3 to about 50 nm, and most preferably from about 5 to about 40 nm. Suitably, the colloidal silica particles have a specific surface area of from about 20 to about 1500, preferably from about 50 to about 900, and most preferably from about 70 to about 600 m ² / g.

The colloidal silica particles preferably have a narrow particle size distribution, i.e., a relatively low standard deviation of the particle size. The relative standard deviation of the particle size distribution is the standard deviation ratio of the particle size distribution to the numerical average particle size. The relative standard deviation of the particle size distribution is preferably lower than about 60% by number, more preferably lower than about 30% by number, and most preferably lower than about 15% by number.

The colloidal silica particles are suitably dispersed in an aqueous solvent in the presence of a stabilizing cation such as K ⁺ , Na ⁺ , Li ⁺ , NH ₄ ⁺ , organic cations, primary, secondary, tertiary and quaternary amines, To form an aqueous silica sol. However, dispersions comprising water-miscible organic solvents, such as lower alcohols, acetone, or mixtures thereof, also preferably contain from about 1 to about 20, more preferably from about 1 to about 10, and most preferably from about 1 to about 10, Preferably in an amount of about 1 to about 5% by volume. However, aqueous silica sols having no additional solvent are preferably used. Preferably, the colloidal silica particles are negatively charged. Suitably, the content of silica in the sol is from about 20 to about 80, preferably from about 25 to about 70, and most preferably from about 30 to about 60 wt%. The higher the silica content, the more concentrated colloidal silica dispersion is produced. The pH of the colloidal silica is suitably from about 1 to about 13, preferably from about 6 to about 12, and most preferably from about 7.5 to about 11. However, the aluminum-modified silica sol has a pH of suitably from about 1 to about 12, preferably from about 3.5 to about 11.

The colloidal silica preferably has an S-value of from about 20 to about 100, more preferably from about 30 to about 90, and most preferably from about 60 to about 90. [

It has been found that dispersions having S-values within these ranges can improve the stability of the resulting dispersion. The S-value characterizes the degree of aggregation of the colloidal silica particles, i.e., the degree of aggregation or microgel formation. The S-value is [J. Phys. Chem. 60 (1956), 955-957 by Iler, R. K. & Dalton, R. L.).

The S-value is dependent on the silica content, viscosity and density of the silica sol. High S-values indicate low microgel content. The S-value represents the weight percentage of SiO ₂ present in the dispersed phase of the silica sol. The degree of microgel can be controlled during the manufacturing process as further described in U.S. Patent No. 5,368,833.

The colloidal silica is added slowly to the polymer under agitation, or the polymer is slowly added to the colloidal silica. The polymer is mixed with colloidal silica particles in a weight ratio of polymer to silica of from 0.2 to 5, more preferably from about 0.5 to 3, and most preferably from about 1 to 2. The temperature of the mixture is preferably 0 to 50 占 폚, more preferably 20 to 40 占 폚.

The neutralizing agent is used to maintain the final pH value of the hybrid binder higher than 8.5, preferably 8.5 to 11, more preferably 9.0 to 10. Organic amines or water-soluble inorganic bases are suitable neutralizing agents for use in the present invention. Preferred neutralizing agents are N-methylmorpholine, triethylamine, dimethylethanolamine, dimethylisopropanolamine, methyldiethanolamine, triethanolamine or ethyl-di-isopropylamine, diethylethanolamine, butanolamine, morpholine , 2-aminomethyl-2-methyl-propanol (AMP), isophoronediamine, or ammonium (NH ₄ OH). The most preferred neutralizing agent is 2-aminomethyl-2-methyl-propanol (AMP), and ammonium.

The neutralizing agent is added at a temperature of 0 to 50 캜, preferably 20 to 40 캜. In one application, the hybrid binders of the present invention are used in an aqueous coating composition.

The aqueous coating compositions of the present invention may be formulated as a coalescing agent, co-solvent, surfactant, buffer, neutralizer, thickener, rheology modifier, dispersant, humectant, humectant, At least one conventional coating aid, including, but not limited to, plasticizers, anti-foaming agents, anti-foaming agents, anti-skinning agents, colorants, flow agents, crosslinking agents and antioxidants.

Formulations of aqueous coating compositions include the steps of selecting and coating with appropriate proportions of the appropriate coating components to provide the final dried paint film with desired properties as well as the paint with special processing and handling properties.

The aqueous coating compositions may be applied by conventional application methods, such as brushing, roller application and spraying methods such as air-jet spraying, airless spraying, airless spraying, hydraulic low pressure spraying, and airless airless spraying.

Suitable substrates include, but are not limited to, for example, concrete, cement board, MDF and particle board, gypsum board, wood, stone, metal, plastic, wallpaper and textiles. Preferably, all substrates are pre-primed with an aqueous or solvent-based primer.

The aqueous coating composition and its application method can affect the paint effect. When the amount of the hydrophilic substance in the aqueous coating composition is too large, the liquid stain repellency becomes poor. Likewise, when the concentration of the hydrophilic substance on the surface of the dry paint film is too high in its application, the liquid stain repellency is poor.

Example

I. Raw materials

II. Test method of acid value on surface and serum

1. Sample preparation

17.5 g of latex was weighed and diluted to 35 g with deionized water and centrifuged at 18,500 rpm for 2 hours at 4 占 폚. After centrifugation, the clear supernatant was carefully decanted off. 17.5 g of the supernatant was diluted to 30 g with deionized water. The polymer was collected and redispersed in 30 g deionized water.

2. Sample titration with 0.50N KOH:

The pH of the diluted supernatant was adjusted to pH = 1.0 with 0.5 N HCl and the pH was adjusted to 1.0 with a Radiometer TTT 80 titrator (from Radiometer America), a RHM 84 Research pH meter from Radiometer America and an Auto Buret ABU80 titration system from Radiometer America And titrated with 0.50N KOH. The serum acid value (mg KOH / dry polymer g) is equal to the KOH volume (ml between two peaks of the first derivative of the titration curve) X (0.5N) X56 / (17.5 X (latex solids)) to the diluted supernatant sample .

The redispersed polymer was titrated in a similar manner. The surface acid value (mg KOH / dry polymer g) is equal to the volume of KOH (between two peaks of the first derivative of the titration curve) X (0.5N) X56 / (17.5 X (latex solids)) versus redispersed polymer.

Example 1

The aqueous hybrid binder A was prepared by the following process: 318.3 g BA, 452.3 g 2-EHA, 889.1 g MMA, 15.56 g MAA, 31.38 g 20% DBS solution and 540 g deionized water were combined and emulsified with stirring to obtain monomer Emulsion. Next, 13.22 g of a 20 wt% DBS aqueous solution and 860 g of deionized water were added to a 5 liter multi-neck flask equipped with a mechanical stirrer. The flask contents were heated to 90 占 폚 under a nitrogen atmosphere. To a stirring flask was added 60 g of monomer emulsion in 23.9 g deionized water, 5.05 g APS. The remaining monomer emulsion and 125 g of deionized water were slowly added over 90 minutes. The reactor temperature was maintained at 88 占 폚. The emulsion feed line for the reactor was then cleaned using 36 g deionized water. The reaction mixture was then stirred at the reaction temperature for 1 hour and then cooled to room temperature. The polymer was then mixed with 2797.3 g colloidal silica Bindzil® 2040 (40% active) over 30 minutes with stirring. The final pH value was adjusted to 9.5 with AMP to obtain hybrid binder A. The solids of Hybrid Binder A were 44.3%. The polymer had a surface acidity of 1.75 mg KOH / dry polymer g, and a polymer had an acid value of 0.24 mg KOH / dry polymer g.

Example 2

The aqueous hybrid binder B was prepared by a procedure similar to the aqueous hybrid binder A (Example 1). A polymer was prepared from a monomer emulsion containing 318.3 g BA, 452.3 g 2-EHA, 881.3 g MMA, 23.34 g MAA, 31.38 g 20% DBS solution, and 540 g deionized water. The polymer was added to 2797.3 g colloidal silica Bindzil 2040 (40% active) over 30 minutes with stirring. The final pH value was adjusted to 9.3 with AMP and hybrid binder B was obtained. The solids of Hybrid Binder B was 44.6%. The surface acid value of the polymer was 2.68 mg KOH / dry polymer g, and the acid value on the serum of the polymer was 1.08 mg KOH / dry polymer g.

Example 3

The aqueous hybrid binder C was prepared by a procedure similar to the aqueous hybrid binder A (Example 1). A polymer was prepared from a monomer emulsion containing 318.3 g BA, 452.3 g 2-EHA, 871.2 g MMA, 33.51 g MAA, 31.38 g 20% DBS solution, and 540 g deionized water. The polymer was added to 2797.3 g colloidal silica Bindzil 2040 (40% active) over 30 minutes with stirring. The final pH value was then adjusted to 9.3 with AMP to obtain the hybrid binder C. [ The solids of Hybrid Binder C was 44.7%. The surface acid value of the polymer was 3.17 mg KOH / dry polymer g, and the acid value on the serum of the polymer was 1.09 mg KOH / dry polymer g.

Example 4

The aqueous hybrid binder D was prepared by a procedure similar to the aqueous hybrid binder C (Example 3). The final pH value was adjusted to 10 with AMP to obtain hybrid binder D. The solids of Hybrid Binder D were 44.6%.

Example 5

Hybrid binder E was prepared by the following process: 707.2 g EHA, 941.8 g MMA, 25.51 g MAA, 8.38 g AM, 31.38 g 20% DBS solution, and 540 g deionized water were combined and emulsified with stirring to produce a monomer emulsion Respectively. Next, 13.22 g of a 20 wt% DBS aqueous solution and 860 g of deionized water were added to a 5 liter multi-neck flask equipped with a mechanical stirrer. The flask contents were heated to 90 占 폚 under a nitrogen atmosphere. 60 g of monomer emulsion was added to a stirring flask followed by addition of 2.51 g Na ₂ CO ₃ buffer in 23.9 g deionized water, 5.05 g APS in 23.9 g deionized water. The remaining monomer emulsion and 125 g of deionized water were slowly added over 90 minutes. The reactor temperature was maintained at 88 占 폚. The emulsion feed line for the reactor was then cleaned using 36 g deionized water. The reaction mixture was then stirred at the reaction temperature for 1 hour and then cooled to room temperature. The polymer was then mixed with 2797.3 g colloidal silica Bindzil® 2040 (40% active) over 30 minutes. The final pH value was adjusted to 9.5 with AMP to obtain hybrid binder E. The solids of the hybrid binder E were 45.8%. The surface acid value of the polymer was 3.42 mg KOH / dry polymer g, and the acid value on the serum was 1.5 mg KOH / dry polymer g.

Example 6

The aqueous hybrid binder F was prepared by a procedure similar to the aqueous hybrid binder E (Example 5). The polymer was added to 2797.3 g colloidal silica LUDOX® TM-40 (40% active) for 30 minutes. The final pH value was then adjusted to 9.2 with NH ₄ OH (25% active) to obtain Hybrid Binder F. The solids of the hybrid binder F was 45.5%.

Example 7

The aqueous hybrid binder G was prepared by a procedure similar to the aqueous hybrid binder E (Example 5). The polymer was added to 2797.3 g colloidal silica Bindzil® CC-40 (40% active) for 30 minutes. The final pH value was then adjusted to 8.5 with NH ₄ OH (25% active) to obtain Hybrid Binder G. The solids of the hybrid binder F was 45.3%.

Comparative Example 8

Aqueous Hybrid Binder H was prepared by a procedure similar to Aqueous Hybrid Binder E (Example 5). The polymer was added to 3279.3 g colloidal silica NS-30 (30% active) for 30 minutes. The final pH value was then adjusted to 8.0 with NH ₄ OH (25% active) to obtain the hybrid binder H. The solids of the hybrid binder H were 38.7%.

Comparative Example 9

Aqueous Hybrid Binder I was prepared by a procedure similar to aqueous Hybrid Binder A (Example 1). A polymer was prepared from a monomer emulsion containing 318.3 g BA, 452.3 g 2-EHA, 896.9 g MMA, 7.78 g MAA, 31.38 g 20% DBS solution, and 540 g deionized water. The polymer was added to 2797.3 g colloidal silica Bindzil 2040 (40% active) over 30 minutes with stirring. The final pH value was adjusted to 9.5 with AMP to obtain Hybrid Binder I. The solids of Hybrid Binder I were 44.5%. The surface acid value of the polymer was 0.98 mg KOH / dry polymer g, and the acid value on the serum of the polymer was 0.07 mg KOH / dry polymer g.

Comparative Example 10

Aqueous Hybrid Binder J was prepared by a procedure similar to Aqueous Hybrid Binder A (Example 1). The polymer was prepared as a two step polymer. The first stage monomer emulsion was prepared from 696.9 g MMA, 255.06 BA, 361.86 g 2-EHA, 33.51 g MAA, 25.10 g DBS (20% active) and 432 g water. The second stage monomer emulsion was prepared from 180.9 g MMA, 63.66 g BA, 90.47 EHA, 6.28 g 20% DBS solution, and 108 g water. After feeding the first stage monomer emulsion, 3.5 g NH ₄ OH (25% active) was added to adjust the pH value to 6.0. The second stage polymer was fed to the reactor at the same rate. The polymer was slowly added to 2797.3 g colloidal silica Bindzil 2040 and the final pH value was adjusted to 9.3 with AMP to obtain hybrid binder J. The solids of Hybrid Binder J was 44.5%. The surface acid value of the polymer was 4.24 mg KOH / dry polymer g, and the acid value in the serum was 1.0 mg KOH / dry polymer g.

Comparative Example 11

The aqueous hybrid binder K was prepared by a procedure similar to the aqueous hybrid binder C (Example 3). The polymer was prepared using the same monomer emulsion (Example 3) and 3.36 g Na ₂ CO ₃ buffer in 23.9 g deionized water was added to the kettle before the monomer feed. The polymer was slowly added to 2797.3 g colloidal silica Bindzil 2040 (40% active) over 30 minutes with stirring. The final pH value was adjusted to 9.5 with AMP and a hybrid binder K was obtained. The solids of the hybrid binder K was 44.8%. The surface acid value of the polymer was 4.73 mg KOH / dry polymer g, and the acid value in the serum was 1.5 mg KOH / dry polymer g.

Comparative Example 12

The aqueous hybrid binder L was prepared by a procedure similar to the aqueous hybrid binder A (Example 1). 837.6 g BA, the 820.9 g MMA, 16.75 g MAA, 31.38 g 20% DBS solution, and 540 g preparing a polymer from a monomer emulsion containing the deionized water, 23.9 g of deionized water of 5.86 g Na ₂ CO ₃ prior to the monomer feed Lt; / RTI > The polymer was slowly added to 2797.3 g colloidal silica Bindzil 2040 (40% active) over 30 minutes with stirring. The final pH value was adjusted to 9.5 with AMP to obtain Hybrid Binder L. The solids of Hybrid Binder L was 44.7%. The polymer had a surface acid value of 6.2 mg KOH / dry polymer g and a serum acid value of 2.39 mg KOH / dry polymer g.

III. Test Methods

Paint formulation

Paint containing different hybrid binders was prepared according to the procedures shown in Tables 1 and 2. The (grind) components described in Table 1 and Table 2 were mixed using a high speed cow disperser. The (let down) components described in Table 1 and Table 2 were mixed using a conventional laboratory mixer.

Paint stability test

Paint was prepared from the hybrid binder according to the procedures of Tables 2 and 3. After manufacture, the paint was stored at room temperature overnight. The viscosity of the Krebs Unit (KU) was recorded using a stormer-type viscometer (according to ASTM D562). The paint was left in an oven for 10 days at < RTI ID = 0.0 > 50 C < / RTI > The Brookfield viscosity of the paint after heat aging was tested as KU2. ? KU = average (KU2-KU1), indicating the storage stability of the paint. The limit value of △ KU was set to about ± 10, which is the allowable level of paint storage stability.

Table 3 shows the effect of the surface acid of the hybrid binder, the acid on the surface of the polymer, and the final pH value on the storage stability of the paint. If the surface acid of the copolymer is from 1.0 to 4.0 mg KOH / g of dry polymer and the acid value in the serum is less than 2.3 mg KOH / g of dry polymer and the final pH value is greater than 8.5, the paint prepared from the hybrid binder will have excellent thermal aging stability .

Claims (10)

a) at least one water dispersible or water soluble polymer comprising from 1 to 10% by weight, based on the dry weight of the polymer, of ethylenically unsaturated monomers having at least one functional group as copolymerized units; And
b) at least one colloidal silica,
Wherein the surface acid number of the water dispersible or water soluble polymer is from 1.0 to 4.0 mg KOH / g of dry polymer, the acid number in the serum is from 0 to 2.3 mg KOH / g of dry polymer,
The final pH value was adjusted to at least 8.5 using a neutralizing agent,
Stable aqueous hybrid binder. The stable aqueous hybrid binder of claim 1, wherein the ethylenically unsaturated monomer is selected from methyl acrylic acid, acrylic acid, acrylamide, methacrylamide, or mixtures thereof. The stable aqueous hybrid binder according to claim 2, wherein the ethylenically unsaturated monomer is methyl acrylic acid. The stable aqueous hybrid binder of claim 1, wherein the surface acid value of the water dispersible or water soluble polymer is 1.75 to 3.43 mg KOH / dry polymer g. The stable aqueous hybrid binder according to claim 1, wherein the acid value of the water-dispersible or water-soluble polymer is from 0.07 to 1.5 mg KOH / dry polymer g. The stable aqueous hybrid binder of claim 1, wherein the colloidal silica is derived from precipitated silica, microsilica, pyrogenic silica, silica gel with sufficient purity, or mixtures thereof. The stable aqueous hybrid binder of claim 1, wherein the final pH value is between 8.5 and 11. The stable aqueous hybrid binder of claim 1, wherein the neutralizing agent is 2-aminomethyl-2-methyl-propanol, ammonium or a mixture thereof. The surface acid value of the water-dispersible or water-soluble polymer is from 1.0 to 4.0 mg KOH / g of dry polymer; A process for the preparation of a stable aqueous hybrid binder according to claim 1, wherein the acid value of the water-dispersible or water-soluble polymer is from 0 to 2.3 mg KOH / g of dry polymer and the final pH value is adjusted to 8.5 or more by the use of a neutralizing agent. A coating composition comprising a stable aqueous hybrid binder according to claim 1.